package com.demo.kit;

import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

public class CipherMessage {
	private String algorithm; // 算法，如DES
	private Key key; // 根据算法对应的密钥
	private String plainText; // 明文

	KeyGenerator keyGenerator;
	Cipher cipher;

	// 函数进行初始化
	CipherMessage(String alg, String msg) {
		algorithm = alg;
		plainText = msg;
	}

	// 加密函数，将原文加密成密文
	public byte[] CipherMsg() {
		byte[] cipherText = null;

		try {
			// 生成Cipher对象
			cipher = Cipher.getInstance(algorithm);
			// 用密钥加密明文(plainText),生成密文(cipherText)
			cipher.init(Cipher.ENCRYPT_MODE, key); // 操作模式为加密(Cipher.ENCRYPT_MODE),key为密钥
			cipherText = cipher.doFinal(plainText.getBytes()); // 得到加密后的字节数组
			// String str = new String(cipherText);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return cipherText;
	}

	// 解密函数，将密文解密回原文
	public String EncipherMsg(byte[] cipherText, Key k) {
		byte[] sourceText = null;

		try {
			cipher.init(Cipher.DECRYPT_MODE, k); // 操作模式为解密,key为密钥
			sourceText = cipher.doFinal(cipherText);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return new String(sourceText);

	}

	// 生成密钥
	public Key initKey() {
		try {
			// 初始化密钥key
			keyGenerator = KeyGenerator.getInstance(algorithm);
			keyGenerator.init(56); // 选择DES算法,密钥长度必须为56位
			key = keyGenerator.generateKey(); // 生成密钥
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return key;
	}

	// 获取Key类型的密钥
	public Key getKey() {
		return key;
	}

	// 获取Key类型的密钥
	public Key getKey(byte[] k) {
		try {
			key = cipher.unwrap(k, algorithm, Cipher.DECRYPT_MODE);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return key;
	}

	// 获取密钥包装成byte[]类型的
	public byte[] getBinaryKey(Key k) {
		byte[] bk = null;
		try {
			bk = cipher.wrap(k);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return bk;
	}
	public static void main(String[] args) {
		String algorithm = "DES"; // 定义加密算法,可用 DES,DESede,Blowfish
        String message = "Hello World. 这是待加密的信息"; // 生成个DES密钥
        Key key;

        CipherMessage cm = new CipherMessage(algorithm, message);
        key = cm.initKey();
        System.out.println(key.toString());
        byte[] msg = cm.CipherMsg();
        System.out.println("加密后的密文为：" + new String(msg));
        // System.out.println("密钥为："+new String(cm.getBinaryKey(key)));

        
        System.out.println(cm.getBinaryKey(key));
        System.out.println("解密密文为：" + cm.EncipherMsg(msg, key));

	}
}
